Why is my PDO Prepared Statement Fetch() Duplicating Results?

PDO Prepared Statement Fetch() Duplicating Results

Issue

A PHP script using PDO prepared statements and fetch() is outputting duplicate data to a CSV file. Each row from the database is echoed twice, resulting in doubled column values.

Analysis

Previously, when not using PDO, the query worked as expected. Therefore, the issue may lie in the usage of fetch().

Resolution

By specifying the desired data retrieval mode when calling fetch(), the duplicate results issue can be resolved. There are two options:

• PDO::FETCH_ASSOC: Returns an array indexed by the column names.
• PDO::FETCH_NUM: Returns an array indexed by the column numbers.

To implement this, modify the code as follows:

<code class="php">while ($rows_get_rows = $result_get_rows->fetch(PDO::FETCH_ASSOC)) {
  $csv .= '"'.join('","', str_replace('"', '""', $rows_get_rows))."\"\n";
}</code>

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